Implement Xgit.RevWalk.RevObject.

lib/xgit/revwalk/rev_object.ex

@@ -0,0 +1,246 @@
+# Copyright (C) 2008, Shawn O. Pearce <spearce@spearce.org>
+# and other copyright owners as documented in the project's IP log.
+#
+# Elixir adaptation from jgit file:
+# org.eclipse.jgit/src/org/eclipse/jgit/revwalk/RevObject.java
+#
+# Copyright (C) 2019, Eric Scouten <eric+xgit@scouten.com>
+#
+# This program and the accompanying materials are made available
+# under the terms of the Eclipse Distribution License v1.0 which
+# accompanies this distribution, is reproduced below, and is
+# available at http://www.eclipse.org/org/documents/edl-v10.php
+#
+# All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or
+# without modification, are permitted provided that the following
+# conditions are met:
+#
+# - Redistributions of source code must retain the above copyright
+#   notice, this list of conditions and the following disclaimer.
+#
+# - Redistributions in binary form must reproduce the above
+#   copyright notice, this list of conditions and the following
+#   disclaimer in the documentation and/or other materials provided
+#   with the distribution.
+#
+# - Neither the name of the Eclipse Foundation, Inc. nor the
+#   names of its contributors may be used to endorse or promote
+#   products derived from this software without specific prior
+#   written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
+# CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
+# INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+# OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+# ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
+# CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+# NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+# LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+# CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+# STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+# ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
+# ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+# PORTING NOTE: Port as a protocol for unparsed placeholder vs specific (parsed) types.
+
+defmodule Xgit.RevWalk.RevObject do
+  @moduledoc ~S"""
+  Shared infrastructure for objects accessed during revision walking.
+  """
+
+  alias Xgit.Lib.Constants
+
+  defprotocol Object do
+    @moduledoc ~S"""
+    Objects made accessible via revision walking will implement this protocol.
+    """
+    alias Xgit.Lib.ObjectId
+
+    @type t :: term
+
+    @doc ~S"""
+    Return the name (object ID) of this object.
+    """
+    @spec object_id(object :: t) :: ObjectId.t()
+    def object_id(object)
+
+    @doc ~S"""
+    Return `true` if the object has been parsed.
+    """
+    @spec parsed?(object :: t) :: boolean
+    def parsed?(object)
+
+    @doc ~S"""
+    Return the git object type of the object.
+
+    This will be one of the `obj_*` types defined in `Constants`.
+    """
+    @spec type(object :: t) :: integer
+    def type(object)
+
+    @doc ~S"""
+    Return the set of flags that has been set on this object.
+    """
+    @spec flags(object :: t) :: MapSet.t()
+    def flags(object)
+
+    @doc ~S"""
+    Returns a new instance of this object with one or more flags added.
+    """
+    @spec add_flags(object :: t, flags :: [atom]) :: t
+    def add_flags(object, flags)
+
+    @doc ~S"""
+    Returns a new instance of this object with one or more flags removed.
+    """
+    @spec remove_flags(object :: t, flags :: [atom]) :: t
+    def remove_flags(object, flags)
+  end
+
+  defmodule Unparsed do
+    @moduledoc ~S"""
+    An object whose contents have not yet been parsed.
+
+    ## Struct Members
+
+    * `flags`: (MapSet) flags associated with this object
+    * `id`: (String) object ID
+    * `type`: (integer) object type (one of `obj_*` constants)
+    """
+    @enforce_keys [:id, :type]
+    defstruct [{:flags, MapSet.new()}, :id, :type]
+
+    defimpl Xgit.RevWalk.RevObject.Object do
+      @impl true
+      def object_id(%{id: id}), do: id
+
+      @impl true
+      def parsed?(_object), do: false
+
+      @impl true
+      def type(%{type: type}), do: type
+
+      @impl true
+      def flags(%{flags: %MapSet{} = flags}), do: flags
+
+      @impl true
+      def add_flags(%{flags: %MapSet{} = flags} = object, %MapSet{} = new_flags),
+        do: %{object | flags: MapSet.union(flags, new_flags)}
+
+      @impl true
+      def remove_flags(%{flags: %MapSet{} = flags} = object, %MapSet{} = new_flags),
+        do: %{object | flags: MapSet.difference(flags, new_flags)}
+    end
+
+    defimpl String.Chars do
+      @impl true
+      defdelegate to_string(object), to: Xgit.RevWalk.RevObject
+    end
+  end
+
+  # abstract void parseHeaders(RevWalk walk) throws MissingObjectException,
+  #     IncorrectObjectTypeException, IOException;
+  #
+  # abstract void parseBody(RevWalk walk) throws MissingObjectException,
+  #     IncorrectObjectTypeException, IOException;
+
+  @doc ~S"""
+  Return the name (object ID) of this object.
+  """
+  defdelegate object_id(object), to: Object
+
+  @doc ~S"""
+  Return the git object type of the object.
+
+  This will be one of the `obj_*` types defined in `Constants`.
+  """
+  defdelegate type(object), to: Object
+
+  @doc ~S"""
+  Returns `true` if the given flag has been set on this object.
+  """
+  def has_flag?(object, flag) when is_atom(flag) do
+    flags = Object.flags(object)
+    MapSet.member?(flags, flag)
+  end
+
+  @doc ~S"""
+  Returns `true` if any of the flags in the list has been set on this object.
+  """
+  def has_any_flag?(object, %MapSet{} = test_flags) do
+    flags = Object.flags(object)
+
+    test_flags
+    |> MapSet.intersection(flags)
+    |> Enum.empty?()
+    |> invert()
+  end
+
+  defp invert(b), do: !b
+
+  @doc ~S"""
+  Returns `true` if all of the flags in the list have been set on this object.
+  """
+  def has_all_flags?(object, %MapSet{} = test_flags) do
+    flags = Object.flags(object)
+
+    test_flags
+    |> MapSet.intersection(flags)
+    |> MapSet.equal?(test_flags)
+  end
+
+  @doc ~S"""
+  Add a flag to this object.
+  """
+  def add_flag(object, flag) when is_atom(flag), do: add_flags(object, MapSet.new([flag]))
+
+  @doc ~S"""
+  Add a set of flags to this object.
+  """
+  defdelegate add_flags(object, flags), to: Object
+
+  @doc ~S"""
+  Remove a flag from this object.
+  """
+  def remove_flag(object, flag) when is_atom(flag), do: remove_flags(object, MapSet.new([flag]))
+
+  @doc ~S"""
+  Remove a set of flags from this object.
+  """
+  defdelegate remove_flags(object, flags), to: Object
+
+  @doc ~S"""
+  Render a string from any struct that implements the `RevObject.Object` protocol.
+
+  Intended to be called by those struct modules.
+  """
+  def to_string(rev_object) do
+    type_str =
+      rev_object
+      |> type()
+      |> Constants.type_string()
+
+    name = object_id(rev_object)
+    flags_str = core_flags_str(rev_object)
+
+    "#{type_str} #{name} #{flags_str}"
+  end
+
+  defp core_flags_str(rev_object) do
+    flag_str(rev_object, :topo_delay, "o") <>
+      flag_str(rev_object, :temp_mark, "t") <>
+      flag_str(rev_object, :rewrite, "r") <>
+      flag_str(rev_object, :uninteresting, "u") <>
+      flag_str(rev_object, :seen, "s") <>
+      flag_str(rev_object, :parsed, "p")
+  end
+
+  defp flag_str(rev_object, flag, flag_char) do
+    if has_flag?(rev_object, flag),
+      do: flag_char,
+      else: "-"
+  end
+end

notes/porting_roadmap.txt

@@ -11,7 +11,6 @@ RevWalk
   RevBlob
   RevCommit
   RevFilter
-  RevObject
   RevTag DEFER?
   RevTree
   StartGenerator DEFER?
@@ -29,7 +28,6 @@ AbstractTreeIterator
   WorkingTreeIterator DEFER?
 
 BlockObjQueue
-  RevObject
 
 BlockRevQueue
   AbstractRevQueue
@@ -71,22 +69,19 @@ ObjectWalk
   ObjectInserter DEFER?
   RevBlob
   RevCommit
-  RevObject
   RevTree
   RevWalk
   RevWalkTestCase CYCLE with RevWalk itself
   TreeFormatter DEFER?
 
 RevBlob
-  RevObject
   RevWalk
 
 RevCommit
   FIFORevQueue
   FooterKey
   FooterLine
   RevCommitParseTest
-  RevObject
   RevTree
   RevWalk
 
@@ -98,15 +93,11 @@ RevFilter ABSTRACT
   RevCommit
   RevWalk
 
-RevObject ABSTRACT
-  RevWalk
-
 RevQueueTestCase
   RevCommit
   RevWalkTestCase
 
 RevTree
-  RevObject
   RevWalk
 
 TestRepository
@@ -120,7 +111,6 @@ TestRepository
   RefUpdate
   RefWriter
   RevBlob
-  RevObject
   RevTag DEFER?
   RevWalk
   TagBuilder DEFER?